La Sportiva Men's Karakorum Hiking Shoe Leather polyurethane sole Karakorum used a new tapered 8mm high density Nylon&reg that provides a smooth flex and protection throughout the boot. This allows for new-matic crampon compatibility and long lasting consistent flex. The 2.8mm Idro-Perwanger leather upper is ideal for water repellency, breathability and durability. IDEAL TERRAIN: general mountaineering and heavy backpacking